RGO-wrapped Ni-P hollow octahedrons as noble-metal-free catalysts to boost the hydrolysis of ammonia borane toward hydrogen generation

Ni-P hollow octahedrons wrapped by reduced graphene oxide (Ni-P H-Oct-rGO) were prepared by phosphorization of the rGO wrapped NiS₂ solid octahedrons (NiS₂ S-Oct-rGO) precursor. The shell thickness of Ni-P hollow octahedrons was ∼20 nm. As a catalyst for the hydrolysis of ammonia borane (AB), the Ni-P H-Oct-rGO exhibits the turnover frequency (TOF) and the activation energy (E_a) of 34.2 ± 0.6 mol_H2 mol_Ni-P⁻¹ min⁻¹ and 40.8 kJ mol⁻¹ under ambient conditions, respectively. This work provides a simple synthetic method to obtain a high activity non-noble metal catalyst for the hydrolytic dehydrogenation of AB. The high surface area of Ni-P hollow octahedron with more active sites, the synergistic effect and interfacial interaction between Ni-P NPs and rGO, and the component and structural stability of Ni-P ensure that the Ni-P H-Oct-rGO present excellent activity and re-usability for the hydrolysis of AB. The as-prepared Ni-P H-Oct-rGO is an ideal candidate with superior catalytic performance and satisfied durable stability towards generating hydrogen, which is an important fuel in practical applications.